The present invention relates to a foamed thermal-insulating material used in insulating devices such as refrigerators, freezers, etc. and to an insulated structure utilizing the foamed thermal-insulating material.
Recently, environmental issues such as the destruction of the ozone layer and global warming, which are influenced by Chloro Fluoro Carbons (CFCs), are receiving close attention. For this reason, reduction in the use of CFCs as a foaming agent has become a very important issue.
Therefore, since hard urethane foam is the leading foamed thermal-insulating material, it is proposed to use a hydrocarbon foaming agent which does not include a halogen molecule.
However, a hydrocarbon is not easily applied as a foaming agent because of combustibility safety, thermal-insulating efficiency quality, and so on. Further, a foamed thermal-insulating material made using a hydrocarbon as a foaming agent is less effective than the foamed thermal-insulating material made by using the present CFC11 foaming agent.
Concerning the above mentioned problem, the present invention aims to provide the foamed thermal-insulating material and the insulated structure filled with the foamed thermal-insulating material that are not inferior to the present foamed thermal-insulating material made by using the CFC11 foaming agent in terms of combustibility safety, thermal-insulating efficiency quality, and so on, when a hydrocarbon is applied as a foaming agent.
To achieve the above mentioned goal, the present invention aims to restrain combustibility of the foamed thermal-insulating material and to prevent the release of halides, which are a cause of acid rain, by adding a non-halogenated organophosphorus compound as an additive to the raw materials of the foamed thermal-insulating material which includes a hydrocarbon foaming agent such as pentane and/or cyclopetane.
In addition, a non-halogenated organophosphorus compound having a molecular weight over 150 as an additive with an OH group as a functional group is reacted and polymerized to an organic polyisocyanates in order to eliminate the possibilities of phosphor corrosion by free ionization to the metal pipes which are disposed inside of the insulated structure and to eliminate the possibilities of food contamination by phosphorus transfer through the plastic board.
Also, organic polyisocyanates that have been polymerized by a non-halogenated organophosphorus compound with active hydrogen are used as the raw materials of the foamed thermal-insulating material which includes a hydrocarbon such as pentane and/or cyclopentane as a foaming agent, in order to restrain combustibility of the foamed thermal-insulating material and to prevent the release of halides, which are a cause of acid rain, caused by the burning of the foamed material for disposal purposes. Further, this composition helps eliminate the possibilities of phosphor corrosion by free ionization to the metal pipes which are disposed inside of the insulated structure, and helps eliminate the possibilities of food contamination by phosphorus transfer through the plastic board despite retaining a phosphor component in the urethane resin.
A Polyol component including at least 5% or more of polyether-polyol, which is obtained from the additional polymerization of ethylenediamine and alkylene-oxide with a hydroxyl value of 350-650 mg KOH/g, is used as the raw materials for the foamed thermal-insulating material which includes a hydrocarbon such as pentane and/or cyclopentane as a foaming agent, in order to improve mutual solubility between a polyol component and a hydrocarbon foaming agent. This maintains the quality of the foamed thermal-insulating material by having a foaming agent equally soluble to the raw material components. Further, this composition improves the insulating efficiency of the foamed thermal-insulating material by raising the addition ratio of a hydrocarbon foaming agent to lower amounts of a co-foaming agent, such as water, and by lowering the ratio of carbonic acid gas, which has a higher gaseous thermal conductivity, among other gas components being retained in the bubbles of the foamed thermal-insulating material.
An acid-blocked catalyst is preferred as a catalyst for the raw materials of the foamed thermal-insulating material which includes a hydrocarbon such as pentane and/or cyclopentane as a foaming agent. This catalyst is used in order to catalytic activation from the beginning to the middle stages of the reaction and by raising the temperature of the pre-mixed raw materials from 5 to 10 degrees Celsius. At this point, due to the use of an acid-blocked catalyst, the foamed thermal-insulating material has a good reaction balance since catalytic activation from the beginning to the middle stages of the reaction is distinctly lowered and the cream time and the gel time will not be extremely shortened in spite of the raised temperature of the raw materials. Also, the problem of filling the cabinets up with foam is eliminated because the foam viscosity is lowered and the uprising-process of foam viscosity is moderated by lowering catalytic activation in the early stage of reaction to make more foam available. In addition, a large amount of catalyst is not needed and a usual prescription of additive is maintained. Accordingly, there are no filling problems such as found with cure and adhesive foams, and a foamed thermal-insulating material with high quality is obtained.